Cancer, in one form or another, is a leading cause of death, and claimed the lives of more than 8.8 million people worldwide in 2015, according to the compiled statistics by WHO (WHO: http://www.who.int/mediacentre/factsheets/fs297/en/; retrieved on Apr. 15, 2017). It is estimated that annual cancer cases will reach 22 million by 2036. Although numerous cancer chemotherapeutics are available today, they often have very narrow therapeutic indices and severe side effects. In addition, cancers can and often do develop resistance to many of these drugs. The fact that there currently are no drugs available that are capable of curing cancer diseases, makes the discovery and development of new anticancer drugs very much needed and the undertaking of such studies is imperative.
Miliusanes are a group of compounds containing an oxo-spirodecane substructure. A few patents have been published related to the compounds containing an oxospirodecane or azaspirodecane or thiaspirocecane substructure (US 2009/0318548A1; US2011/021624A1 and WO2011098433A1).
In US 2009/0318548A1, the compounds of formula (VI) are synthesized. However, no anticancer data is reported therein.

In US2011/021624A1, compounds of formula (VII) are synthesized. However, the representative compound is reported to show weak cytotoxicity against MDA-MB-435, HCT116, A549 and Hela cancer cells (IC50 values in the range of 17-42 μM).

In WO2011098433A1, compounds of formula (VIII) are synthesized. The compounds have a chemical structure containing a biphenyl group, and are reported to have tumor inhibition activity by inhibiting fatty acid synthesis.

Thus, miliusanes compounds with more potent anticancer activity and low toxicity are needed.
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